Three-phase reactance coil



Nov. 13 1923.

A. NYMAN THREE-PHASE REACTANCE COIL' Filed June 19, 1918 2 Sheets-Sheet1 WITNESSES: y'fiwwf AT'T ORNEY Patented Nov. 13,

UNITED STATES PATENT OFFICEQ;

ALEXANDER NYHAN, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOB TO WESTING-HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYL VANIA.

THREE-PHASE REACTANCE COIL.

Application filed June 19, 1918. Serial No. 240,835.

To all whom it may concern:

Be it known that I, ALEXANDER NYMAN, a citizen of Finland, and aresident of \Vilki'nsburg, in the count of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in Three-PhaseReactance Coils, of which the following is a Specification. 1

My invention relates to current-limiting reactance coils and it hasspecial relation to coils which are adapted to be inserted in polyphasecircuits to limit to safe values the abnormal current flow therein thatmay be occasioned by short circuits or by other unusual conditionsconducive to the flow of ab-' normally high currents.

Heretofore, in polyphase power systems and particularly in'3-phasesystems, it has been customary to insert, in each line of the polyphasesystem, acurrent-limiting reactance coil. Such schemes have given riseto large and unwieldy coil units which are especially undesirable whereeconomy of floor space is desired. It has frequently been" necessary,moreover, to space the coils of the separate phases far enough apart toeliminate the inductive interference which may be occasioned b the fluxgenerated by one or more of the 0011s acting upon the other coils.

Furthermore, when it is desired to install 3-phase reactors which shallcarry heavy currents, the usual type of construction, in which the coilsare placed one above another, has sometimes failed. to give entiresatisfaction because of the circulating currents which may beset up inthe parallel cables of which each coil is composed: It is, of course,well understood that, forgcurrents exceeding a certain value, two ormore cables in parallel are generally used to give sufficientcurrentcarrying capacity for such a reactor. g

In 3-phase reactance coils, as at present constructed, there has alwaysbeen more or less of a phase distortion occasioned by the method ofplacing these coils in position. This has been inevitable since nomethod has heretofore been developed of so disposing polyphase coilscarrying currents which are out of phase with res ect to each other,that the fluxes generated y such currents shall not act inductively uponthe associated coil units of the .reactor in an undesirable manner.

Finally, it is often necessary to arrange even direct-current circuits,which contain coils, in such manner that totally independent currentsmay be carried b such associated coils without any change msuch currentsproducing an undesirable inductive effect upon associated coils inproximity thereto. 7

It is, therefore, an object of my invention to so dispose a plurality ofcoil units, either with or without a frame for bracing. the same, insuch manner that absolute symmetry shall be maintained between said coilunits. This s mmetry will, in turn, cause any undesirab e fluxes whichmay thread the associated coil units to be perfectly neutralized and,therefore, perfect phase relationship will be maintained between thefluxes generated by the several cbil units. 7

Moreover, by so disposing a plurality of coil units in universalsymmetry, the space required for a given current ca acity will begreatly decreased, on account 0 the fact that all of the space, which itis desired shall be occupied by said reactance coils, will be taken upwithout, in any way, producing inductive interference between closelyassociated coil units.

Moreover, by so disposing the coils in the above-mentioned arrangement,very heavy currents may be carried'by a number of coils in parallelwithout said parallel coils being subjected .to the initiation thereinof circu+ lating currents which, as has been heretofore noted, are quiteundesirable.

Finally, it is an object of myfinvention to provide an arrangement of aplurality-of coil units whereby a number 0 direct-current circuits,which contain coils in proximity to each other and which carry totallyindependent currents, may be maintained in said desirable proximitywithout any one of the coils being affected inductively by a change ofcurrent condition which may take place in any of the associated coils.

For a better understanding of my invention, reference may be had to theaccompanyin drawing in which:

Fig. 1 is a diagram illustrating the mannet in which a reactance coil ofmy improved construction may be inserted in a polyphase distributionsystem; Fig. 2 is a plan view of the coil indicated in Fig. 1; Figs. 3and 4 are elevational sectional views taken on the line 1-1 of Fig. 2and illustrate the manner in which the coil units are secured in placethrough the use of vertically extending and horizontall diagram s owinfluxes in four the associated coil units; while Fig. 6 is a vectordiagram illustrating the manner in which the fluxes threading thevarious coil units of Fig. 5 are added vectorially to obtain substantialneutralization.

Referrin now to Fig. 1, a poly-axial reactance coi 1 is shown connectedin circuit with the polyphase lines 2, 3 and 4, said lines carryingcurrent supplied by an alternatingcurrent source 5, here shown as apolyphase alternator.

The reactance coil is composed of a plurality of airs of coil units 6and 7 8 and 9 and 10 an 11, and it will be observed that the coil unitsof each pair are oppositely disposed, with their axes in alinement, andthat the coil units of the respective pairs are connected in series inthe line conductors-2, 3 and 4-.

The coil units 6 7 8, 9, 10 and 11 are supported within a slieletonframe, each of the six sides of which comprises two members disposed atright angles to each other, and at angles of forty-five degrees withreference to the adjacent side planes of the frame. For a more detaileddescription of the frame, reference may be had to Fig. 2 wherein members12 are shown as two bars disposed at right angles to each other and eachhaving its ends twisted into a plane at right angles to that of the bodyportion.

The frame members which constitute the side of the frame that isopposite to the side shown in Fig. 2 are duplicates of those shown andeach of the remaining four sides of the frame comprises two bar members13 that are disposed at right angles to reach other and at forty-fivedegree angles with reference to the planes of the sides comprising thebar members 12. The ends of each member 13 are bent outwardly intoplanes that are substantially parallel to the adjacent ends of the bars12 and the three adjacent bar ends of each set are fastened tother bybolts 14 and are suitably insuated from each other and from the bolts,as indicated.

Cleat-securing members 15, of which there are four for each coil, aresecured to the bar members 12 and 13 by bolts 16-16, and

extending cleats; Fig. 5 is a.

the relationship of the within these retaining members are placed cleats17 which are provided with recesses 18 in which the coil units are woundand by means of which the coil units, after being wound, are bracedagainst strains which may be imposed thereupon by short circuitsoccurring on the s stem.

It will be observed that, y constructing a frame in the mannerindicated, a minimum amount of material is used and, at the same time, astrong cubical frame is built up upon the interior of which the coilunits may be mounted in universal symmetry.

The operation of winding the coil units within the frame to constitutemy reactance coil is as follows 2-- The Wire or cable, 4, for instance,is led through an insulator 19, which is located at the intersection ofthe heretofore described bar members 13, and is then wound aboutthecleats 17, in turns of successively decreasing diameters, until thedesired length of wire or cable has been wound. For purposes ofillustration, I have shown three layers of cable so wound as toconstitute one of my coil units and while I have shown in Figs. 2 and 3the cable as wound upon cleat members that are disposed transversely,with refer ence to the coil turns, it will be understood that analternative construction, com rising cleat members disposed turns, maybe employe if desired, such cleat members being shown in Fig. 4.

Furthermore, it will be observed that my coil units are so wound thatthey are substantially in the form of frustums of pyramids or-cones and,having such form, it possible to dispose six of them within a cubicalframe in such manner that practically the entire space within the frameis utilized to its maximum extent. After one coil unit, for instance,unit 11, has been wound in the manner above indicated, the cable iscarried across to the four cleats attached to the directly opposinginterior face of the frame and the process of Winding is there repeated,with the difference that the conical mructure is reversed, and thediameters of the succeeding turns are now successively increased untilthe desired length of cable has been wound. The cable is then carriedout through an insulator 20 inserted at the intersection of the twocross pieces, as indieated. It will be observed, therefore, that myinvention contemplates the use of a plurality of coil units which arearranged in sections by pairs, one of each pair being secured todirectly opposing interior faces of a polyhedral frame, and each sectionthus formed bein inserted in series circuit relationship with one phaseof the polyphase system.

Referring to Fig. 5, the manner in which such a poly-axial reactancecoil will accom arallel to t e coil 6 threadin 1,47a,ae2

plish the com lete maintenance of phase rementioned coils 10 and 11,will also have fluxes initiated therein as indicated at 23 and 24,'respectivel onsidering now the flux of any one coil and rememberingthat such consideration applies to all of the coil units eqlually, sincethey are arranged in universa symmetry, it will be observed that fluxfrom coil 10, as well as passing directly across and through itscompanion coil 11, will also branch out into space in all direc tions,and portions thereof will thread through the coils 8 and 9. Let us desiate these portions by 25 and 26. It wi l, of

course, be understood that, in the coils which are mutuallyperpendicular to the four coils shown, a like threading of flux will beproduced. In short, each and every coil unit of my poly-axial reactancecoil wi l have fluxes therethrough from every other associate coil, theflux coming from its companion coil, which is disposed directlyopposite, and the four equal fluxes, which are constrained to thread;therethrough, and which are initiated in, the four coils situatedperpendicular thereto.

Referring now to Fig. 6, the manner in which these various fluxescombine to produce a constant mutual inductive effect on each other isillustrated. Similar vectors denote similar fluxes, as noted in Fig. 5.Considering, for instance, the vector indicating the flux 23 which isproduced by the coil 8. The flux 25 emanating from coil 10, will threadthrough the coil 8 and, it will be observed, is in a direction oppositeto that of the flux initiated in said coil. Further more, a flux 26initiated in coil 10 will thread through the coil 9 and there add to theflux 24 from the latter coil. It is obvious, of course, that the fluxes25 and 26, since they are initiated by the same current, are in phasewith each other and we may, therefore, represent the direction andamount of the same by vectors 25 and 26. If now, vector 23 is combinedwith vector 25 the resultant will be vector 27. It will be observedthat, in such addition, the vector 25 is, in reality, subtractedvectorially from vector 23.

On the other hand, the vector 26, which represents a flux tending to actin the same direction as flux 24, will be vectorially added thereto anda resultant 28 be obtained by such combination. By the proper vectorialaddition of the fluxes 27 and 28, the combined vector 23-24 is obtainedand it will be observed that this is the same flux which we assumed waspresent in the two oppositely disposed coils 8 and 9, without aconsideration of the effect thereupon of fluxes initiated in associatedcoils.

It will be apparent, therefore, that, by the use of a reactor, ashereinbefore described, polyphase currents may be passed through aplurality of coil units which are disposed in close roximity without, inany way, producing inductive interference between the several coils.

a reactor havin a hexahedral frame to which are secure six coils, Idesire that my invention shall not be limited to the specific number ofcoils or to the specific number of phases which are indicated forurposes of illustration. It isentirely possible that it may be desirableto construct a polyhedral coil which shall be capable of insertion inmore than three phases and, since such a coil would require more thanthe number of coil units which I have used for purposes of illustration,I desire that the broadest possible interpretation be placed upon theappended claims.

While I have herein shown and described Again, I have designated mycoils as frusto-conical in form. However, since a cone, genericallspeaking, is nothing more than a pyrami havin an infinite number ofsides, I wish it to understood that a cone having the form of a pyramidmay be used if it is desired to allot the necessary space which such aform of coil would occupy. Moreover, while ,the coils, as shown in thehereinbefore described reactor, are substantially short frustums, itwill be furthermore understood that such description does not precludethe use of a coil which may be perfectly conical in shape, since such acoil is nothing more than a frustum of a cone, the upper base of whichis of zero area.

Moreover, I desire that the use of the arrangement of a plurality ofcoils which I have shown shall not be limited to alternating-currentpractice. There has been frequent demand for an arran ement of coilswhich are carrying indepen ent direct currents, whereby the circuits andcoils carrying such currentscould be disposed in proximity to each otherand have no inductive interference occasioned therebetween, and Itherefore wish it to be understood that the arrangement of coils hereindescribed and claimed may be readily applied in directcurrent practice.

Furthermore, while I have shown my coil units as comprising equal terms,I have not limited the appended claims to such an arrangement, since itis quite possible that some special designs of coils may demand more orless turns in one unit than in others tion with a and, under suchconditions, the only limitin feature would-be the t pe of frame whicwould be used; that is, it might be desirable '?ap licable to severalsituations, I desire that 'on y such limitations shall be placed upon myinvention as are imposed by the prior art or are specifically pendedclaims.

I claim as my invention:

set forth in the apinter- 1. A tri-axial reactance coil having sectinaxes.

2. reactor comprising a plurahty of coils mounted on rectilinear,intersecting axes.

3. A reactor, comprising a plurality of coil units, the axes of saidcoil units being so disposed as to intersect.

4. A reactor, comprising a plurality of coils, having symmetricallydisposed, intersecting axes.

5. A reactor comprising a plurality of coil units of substantiallyfrusto-conical shape having independent axes and symmetrically mountedon a cubical frame.

6. A reactor'comprising a plurality of multi-sectioned reactance coils,said sections being symmetrically mounted on a polyhedral frame.

7. A muti-sectioned reactance coil, said sections being mounted on apolyhedral frame, and being attached to faces of said polyhedral framedisposed in relative angularrelation. L

'8. A- multi-sectioned reactance coil comprising equal .sections,-one ofsaid sections being attached to each face of a polyhedral frame. 1

9. In a polyphase reactor, the combination with a plurality ofsingle-phase coils, of a polyhedral frame, each of said coils being sodisposed on said frame with respect to the remainder of the coils thatthe reactance of each coil is independent of the flux generated by everyother coil.

10. In a polyphase reactor, the combination-with a plurality of coilunits, of a polyhedral frame, one of said coil units bemg attached toeach face of said polyhedralfi frame.

11. In a polyphase reactor, the combinalurality of single-phase coils,of a polyhe ral frame, said coil being so disposed with respect to theremainder of the coils on the interior of said frame that the reactanceof each coil is independent of the flux generated by every other coil.

12. In a polyphase reactor, the cornbition with a plurality of coilunits, of a polyhedral frame, one of said coil units being attached toeach face of said polyhedral frame, and said coil units beingsubstantially similar and of such shape that they occupy substantial]the entire available space within said rame,

13. In a polyphase reactor, the combination with aplurality of coilunits, of a polyhedral frame, one of said coil units be ing attachedto'each face of said polyhedral frame andpsaid coil units beingsubstantially frusto-conical in form.

14. In a polyphase reactor, the combinat1on with a plurality of coilunits, of a polyhedral frame, said coil units being arranged onintersecting axes within said frame.

15. In a polyphase reactor, the combination with a plurality of coilunits, of a polyhedral frame, said coil units being so arranged onintersecting axes within said frame that they are mutually perpendicularto each other.

16. In a polyphase reactor, the-combination with a plurality of coilunits, of a polyhedral frame, said coil units being symmetricallyarranged on intersecting axes around a point within said frame.

17. In a polyphase reactor, the combination with a plurality of coilunits, of a polyhedral frame, said coil units being disposed onintersecting rectilinear axes and arranged symmetrically around acentral point Within said frame.

18. In a polyphase reactor, the combination with a plurality of coilunits, of a hexahedral frame, one of said coil units being attached toeach face of said hexahedral frame.

19. In a polyphase reactor, the combination with a plurality of coilunits, of a hexahedral frame,- said-coil units being disposed Withinsaid frame and one of said coil units being secured to each face of saidframe.

20. In a polyphase reactor, the combination with a plurality of coilunits, of a hexahedral frame, said coil units being disposed within saidframe and one of said coil units being secured to each face of saidframe, the coil units attached to directly opposite faces beingconnectedin series.

21. In a polyphase reactor, the'combination with a plurality of coilunits, of.a hexahedral frame, said coil units being disposed within saidframe and .one of said coil units being secured to each face of saidframe, the coil units attached to directly oppositefaces being connectedin series to form sections mutually perpendicular to each other.

- 22. In a polyphase reactor, the combination with a plurality of coilunits, of a hexahedral frame, said coil units being dis.- posed withinsaid frame and one of said coil units being secured to each face of saidframe, the coil units attached to directly opposite faces beingconnected in series to form sections mutually perpendicular to eachother, each of said sections being adapted for connection in one phaseof a polyphase distribution system.

23. The combination with a. plurality of conductors comprising apolyphase system, of a set of n reactance coil units, said set of m 0011unlts being arranged in sectlons, each of a set of n reactance coilunits, said set of coil units being arranged in 5 sections,

and a polyhedral frame having n sides, each of said sections beingadapted for connection in one phase of said polyphase system and one ofsaid coil units being secured to each side of said n-sided frame.

25. The combination with a plurality of conductors comprising apolyphase system, of a set of n reactance coil units, said set of coilunits being arranged in sections, and

ALEXANDER N YMAN.

